Ngk Insulators, Inc.

Takatoshi Nehagi

Tomohiro Yamada

Takao Ohnishi

Hirofumi Yamaguchi

Tatsuo Kawaguchi

Shoichiro Yamaguchi

Kunihiko Yoshioka

Masato Komazawa

Tetsuya Hatta

A method for inspecting a piezoelectric element includes first-inspection-signal application step of applying to the piezoelectric element a first inspection signal Vp() having a first predetermined voltage waveform; first-characteristic-value measurement step of measuring, as a first characteristic value, an electrical characteristic value of the piezoelectric element after application of the first inspection signal; second-inspection-signal application step of applying to the piezoelectric element a second inspection signal Vp() having a second predetermined voltage waveform and an electrical power greater than that of the first inspection signal; second-characteristic-value measurement step of measuring, as a second characteristic value, the electrical characteristic value of the piezoelectric element after application of the second inspection signal; and anomaly determination step of determining whether or not the piezoelectric element is anomalous on the basis of a value corresponding to the difference between the measured second characteristic value and the measured first characteristic value.

Inspection method, inspection apparatus, and polarization method for piezoelectric element

In an inspecting method of a piezoelectric/electrostrictive actuator having a piezoelectric/electrostrictive element and two or more electrodes, the frequency response characteristics is picked up when a vibration is given to the piezoelectric/electrostrictive actuator, and the amount of displacement of the piezoelectric/electrostrictive actuator is predicted by the frequency response characteristics. The piezoelectric/electrostrictive actuator is precisely inspected without dissolution and destruction and without actual driving as a product.

Inspecting method of elastic body, inspecting apparatus thereof, and dimension predicting program thereof

A piezoelectric/electrostrictive film-type device is provided which includes a ceramic substrate having a thin diaphragm portion and a peripheral thick portion, a lower electrode, an auxiliary electrode, a piezoelectric/electrostrictive film, and an upper electrode. The lower electrode, the auxiliary electrode, the piezoelectric/electrostrictive film, and the upper electrode are layered in that order on the ceramic substrate. The upper electrode has a length of 30 to 70% relative to the length of the thin diaphragm portion, and preferably has a width of 70% or more relative to the width of the thin diaphragm portion.

Piezoelectric/electrostrictive film-type device

A first electrode and a second electrode are provided in separation on a main surface of a substrate made of a ferroelectric single crystal. A first voltage is applied between the first electrode and the second electrode, for example, on condition that the first electrode is positive and the second electrode is negative, to generate and grow a first polarization-inverted portion toward the second electrode from the first electrode. Then, the distance between the first electrode and the second electrode is changed, and a second voltage is applied between the first electrode and the second electrode on the same condition, to generate and grow a second polarization-inverted portion, in a different area from that of the polarization-inverted portion, toward the second electrode from the first electrode.

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Seto, Japan

Takatoshi Nehagi